This application proposes to continue the National Health and Aging Trend Study (NHATS), which aims (1) to promote scientific inquiry into late-life disability trends and dynamics, their antecedents and correlates, and disparities therein and (2) to advance study of the social and economic consequences of late-life disability for individuals, families, and society. To achieve these aims, in the next 5-year cycle (2014-2018) we will: (a) Collect data in person from the original NHATS cohort annually, including: continued collection of the enhanced disability protocol and supplemental questions on consequences including subjective and economic wellbeing, living and care arrangements, and quality of end of life; collection of dried blood spots, some to be assayed to foster study of the biologic risk for disability progression, and others to be stored for future use; enhancements to the NHATS interview in key understudied areas of potentially growing importance-use of rehabilitation services aimed at recovery from disability, and the service environment and related amenities that promote independent functioning in retirement and senior community settings-and incorporating new modules submitted by the broader research community. (b) Replenish the sample in Round 5 (2015). Replenishment will be implemented in such a way that NHATS maintains the ability to produce 5-year age estimates (including 90+) and Black-White comparisons. (c) Clean, document and disseminate public use files online and continue to make Medicare claims and other sensitive and restricted files available using established procedures. (d) Undertake methodological studies to improve the efficiency of data collection in future rounds, including testing the sensitivity of key estimates to differential follow-up periods and applying modern measurement approaches such as Item Response Theory (IRT) to measures of capacity. The overarching goal of NHATS is to be a platform for scientific inquiry to guide efforts to reduce disability, maximize functioning, and enhance older adults' quality of life. Research using NHATS will foster research to design multi-factor interventions to reduce late-life disability, and will support comprehensive modeling of outcomes of the disability process including living and care arrangements, expenditures, economic well-being, and quality of life.